Properly export blender scene with materials format to three.js scene
As of October 2018, glTF 2.0 supports three material types: metal/rough PBR, spec/gloss PBR, and unlit/shadeless.

We are working on adding support for the Principled BSDF node to the Khronos Group Blender exporter. That work is in progress, and happening in a new repository (https://github.com/KhronosGroup/glTF-Blender-IO) which includes both an importer and an exporter. I'd recommend trying that for now. Note that some inputs to the Principled BSDF node (like anisotropy) are not currently part of glTF's metal/rough PBR definition, and will be ignored.

Other material types may be more or less difficult to convert into one of the supported glTF materials.